Method for preparing dispersions of precious metal nanoparticles and for isolating such nanoparticles from the dispersions

• Main Authors: FARRELL BRENDAN P, MATIJEVIC EGON, GOIA DAN V, MORROW BENJAMIN, BALANTRAPU KRISHNA
• Format: Patent
• Language: Chinese; English
• Published: 20.11.2013
• Subjects: ADHESIVES; CASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; DYES; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POLISHES; POWDER METALLURGY; THEIR RELEVANT APPARATUS; TRANSPORTING; WORKING METALLIC POWDER

The present invention is directed to a method for preparing colloidal dispersions of precious metal nanoparticles selected from the group consisting of Pt, Au, Pd, Ag, Rh, Ru and mixtures or alloys thereof, and to a method for isolating such precious metal nanoparticles from these colloidal dispersions. The colloidal dispersions are prepared by reducing suitable precious metal precursor compounds in aqueous alkaline solutions at reaction temperatures between 40 and 70° C. and a pH>=12.0 in the presence of polysaccharides with average molecular weights (Mw) in the range of 300,000 to 1,000,000. The precious metal nanoparticles are isolated after decomposing the polysaccharide by heating the colloidal dispersions to temperatures >80° C. The nanoparticles can be used for the manufacture of core/shell-type catalyst materials and for electronic, decorative and medical applications.